Red-Emitting Latex Nanoparticles by Stepwise Entrapment of β-Diketonate Europium Complexes

The core-shell structure of poly(St-co-MAA) nanoparticles containing β-diketonate Eu³⁺ complexes were synthesized by a step-wise process. The β-diketonate Eu³⁺ complexes of Eu (TFTB)₂(MAA)P(Oct)₃ [europium (III); 4,4,4-Trifluoro-1-(2-thienyl)-1,3-butanedione = TFTB; trioctylphosphine = (P(Oct)₃); methacrylic acid = MAA] were incorporated to poly(St-co-MAA). The poly(St-co-MAA) has highly monodispersed with a size of 300 nm, and surface charges of the poly(St-co-MAA) are near to neutral. The narrow particle size distribution was due to the constant ionic strength of the polymerization medium. The activated carboxylic acid of poly(St-co-MAA) further chelated with europium complex and polymerize between acrylic groups of poly(St-co-MAA) and Eu(TFTB)₂(MAA)P(Oct)₃. The E_m spectra of europium complexes consist of multiple bands of E_m at 585, 597, 612 and 650 nm, which are assigned to ⁵D₀→⁷F_{J (J = 0-3)} transitions of Eu³⁺, respectively. The maximum E_m peak is at 621 nm, which indicates a strong red E_m characteristic associated with the electric dipole ⁵D₀→⁷F₂ transition of Eu³⁺ complexes. The cell-specific fluorescence of Eu(TFTB)₂(MAA)P(Oct)₃@poly(St-co-MAA) indicated endocytosis of Eu(TFTB)₂(MAA)P(Oct)₃@poly(St-co-MAA). There are fewer early apoptotic, late apoptotic and necrotic cells in each sample compared with live cells, regardless of the culture period. Eu(TFTB)₂(MAA)P(Oct)₃@poly(St-co-MAA) synthesized in this work can be excited in the full UV range with a maximum E_m at 619 nm. Moreover, these particles can substitute red luminescent organic dyes for intracellular trafficking and cellular imaging agents.

A luminescent europium complex for wide-range pH sensors and sensor microtiterplates

Luminescent sensor membranes and sensor microplates are presented for continuous or high-throughput wide-range measurement of pH based on a europium probe.

Turn-on and Ratiometric Luminescent Sensing of Hydrogen Sulfide Based on Metal-Organic Frameworks

The sensing of hydrogen sulfide (H₂S) has become a long-time challenging task. In this work, we developed a general strategy for sensing of H₂S utilizing postsynthetic modification of a nano metal-organic frameworks (MOF) UiO-66-(COOH)₂ with Eu³⁺ and Cu²⁺ ions. The nano MOF Eu³⁺/Cu²⁺@UiO-66-(COOH)₂ displays the characteristic Eu³⁺ sharp emissions and the broad ligand-centered (LC) emission simultaneously. Because H₂S can strongly increase the fluorescence of Eu³⁺ and quench the broad LC emission through its superior affinity for Cu²⁺ ions, the MOF Eu³⁺/Cu²⁺@UiO-66-(COOH)₂ exhibits highly sensitive turn-on sensing of H₂S over other environmentally and biologically relevant species under physiological conditions. Furthermore, this approach for fluorescent turn-on sensing of H₂S is expected to extend to other water-stable MOFs containing uncoordinated -COOH.

Substantial luminescence enhancement in ternary europium complexes by coordination of different ionic ligands

We demonstrate in a general and comprehensive manner that a substantial enhancement of luminescence in europium complexes can be achieved by increasing ionic ligand diversity. The measured boosts in quantum efficiency ranged from 100% to 543%.

A paper-based lanthanide smart device for acid–base vapour detection, anti-counterfeiting and logic operations

A paper-based lanthanide smart device was designed for naked-eye detection of acid–base vapors with quick response and good reversibility; the applications of this device were also expanded to anti-counterfeiting and logic operations.

Near-infrared luminescence of Nd3+ and Yb3+ complexes using a polyfluorinated pyrene-based β-diketonate ligand

Highly efficient near-infrared emitting Nd³⁺ and Yb³⁺ complexes have been developed based on a new polyfluorinated pyrene-appended β-diketonate ligand.